Digital Photographer - UK (2020-01)

You may think that apertures are only about

depth of field, but they can also be used to

reduce or increase the amount of motion you

record. The more you stop the aperture down,

the slower the shutter speed gets to maintain

correct exposure, and the more you open up

the aperture, the faster shutter speed gets.

For example, let’s say you’re shooting a

waterfall at f8 and you’re getting a shutter

speed of 1/30sec. You’re not going to record

much movement in the water at 1/30sec, but

if you stop the lens down to f16, the shutter

speed will drop to 1/8sec and you’ll see a big

difference. This approach can also be used to

greater effect when using a 10-stop or similar

ND filter to record motion in a scene – if you’re

getting 30 seconds at f8, you’ll get one minute

at f11 and two minutes at f16.

The comparison set of images here shows

what a difference changing the lens aperture

can make when you want to record motion.

With the lens wide open at f2.8 there is some

blurring in the water, but not enough. As

the lens is stopped down, the shutter speed

becomes slower and the degree of motion in

the waterfall increases, until at f32 a two-

second exposure turns the water silky smooth.

Add a sense of action to

shots of moving subjects

Use small apertures

to record motion

Below

Zoomburst effect

This striking image was

created by zooming

the lens through its

focal length range

while shooting with a

slow shutter speed

Right

Sway and swirl

Different apertures

can have a dramatic

effect on motion –

it can affect more

than just an image’s

depth of field

Right below

Flowing water

Stopping down

the aperture will

help you capture

a sense of motion

that brings water

scenes alive

5

“ What a difference

changing the lens

aperture can make”

f2.8 and 1/60sec

f11 and 1/4 sec

f4 and 1/30sec

f16 and 1/2 sec

f5.6 and 1/15sec

f22 and 1 sec

f8 and 1/8sec

f32 and 2 secs

Techniques

Youmaythinkthataperturesareonlyabout

depthoffield,buttheycanalsobeusedto

reduceorincreasetheamountofmotionyou

record.Themoreyoustoptheaperturedown,

theslowertheshutterspeedgetstomaintain

correctexposure,andthemoreyouopenup

theaperture,thefastershutterspeedgets.

Forexample,let’ssayyou’reshootinga

waterfallatf8andyou’regettingashutter

speedof1/30sec.You’renotgoingtorecord

muchmovementinthewaterat1/30sec,but

ifyoustopthelensdowntof16,theshutter

speedwilldropto1/8secandyou’llseeabig

difference.Thisapproachcanalsobeusedto

greatereffectwhenusinga10-stoporsimilar

NDfiltertorecordmotioninascene–ifyou’re

getting 30 secondsatf8,you’llgetoneminute

atf11andtwominutesatf16.

Thecomparisonsetofimageshereshows

whatadifferencechangingthe lens aperture

canmakewhenyouwanttorecord motion.

Withthelenswideopenatf2.8 there is some

blurringinthewater,butnotenough. As

thelensisstoppeddown,theshutter speed

becomesslowerandthedegree of motion in

thewaterfallincreases,untilat f32 a two-

secondexposureturnsthewater silky smooth.

Addasenseofaction to

shotsofmovingsubjects

Use small apertures

to record motion

Below

Zoombursteffect

Thisstrikingimagewas

createdbyzooming

thelensthroughits

focallengthrange

whileshootingwitha

slowshutterspeed

Right

Swayandswirl

Differentapertures

canhaveadramatic

effectonmotion–

itcanaffectmore

thanjustanimage’s

depthoffield

Rightbelow

Flowingwater

Stoppingdown

theaperturewill

helpyoucapture

asenseofmotion

thatbringswater

scenesalive

5

“Whatadifference

changingthelens

aperturecanmake”

f2.8and1/60sec

f11and1/4sec

f4and1/30sec

f16and1/2sec

f5.6and1/15sec

f22and 1 sec

f8and1/8sec

f32 and 2 secs

Techniques